WASHINGTON — The Air Force is taking aim at its big costs of fuel and flight this week, temporarily halting training operations for 12 active duty fighter and bomber squadrons across the United States in order to save nearly $300 million.

Details emerging Wednesday underscored the sweeping effect of the service’s move to slash 45,000 hours of flight training between now and Oct. 1. The cuts will hit squadrons in eight fighter wings in at least seven states and the Air Warfare Center at Nellis Air Force Base in Nevada. Bomber squadrons also will likely be affected, but it will be up to the military’s Global Strike Command to determine how to allocate the new flight restrictions.

The cuts, forced by congressionally-mandated spending reductions for this fiscal year, won’t affect current military operations, such as fighters in Afghanistan or bombers training over South Korea. But the Air Force warned that they will have a ripple effect, sharply reducing the service’s ability to be prepared for future operations because pilots must meet minimum flight hour requirements in order to fly.

With fuel, maintenance and personnel eating up a significant portion of its budget, the Air Force looked to the training flights to find savings.

The Air Force’s budget chief, Maj. Gen. Edward Bolton, said large chunks of the service’s budget are eaten up by military and some civilian personnel costs, contract obligations, and money to keep bases and facilities open. The Air Force also has to fund much of the major drone flights over Afghanistan, the analysis of the data, the country’s ground and air-based missile defense system and its nuclear arsenal So, he said, cuts have to be found in flying hours, civilian furloughs and weapons system repairs.

The stand-down started Tuesday for eight of the squadrons. The other four are currently deployed, so when they return from their current operations they will delay the resumption of training flights until the end of the fiscal year, according to the Pentagon.

Defense officials said that while cutting flying hours was a difficult decision, it had to be done in order for the Air Force to maintain its ongoing critical support for combatant commanders around the world, including those in Afghanistan and hotspots in the Middle East and Asia. Over the past month, fighters and bombers have been participating in the joint U.S.-South Korea military exercises that have enraged North Korea.

Lt. Gen. Mark Ramsay, director of force structure and resources for the Joint Chiefs of Staff, said the Air Force had to make the conscious decision to stand down the 12 combat squadrons in order to find savings without affecting ongoing combat operations.

“Certainly they don’t want to have to do that,” he told reporters on Wednesday. “I think the president is aware that there are some arrows in the quiver that are going to be affected as the year goes by.”

According to the Air Force, air crews, on average, “lose currency” to fly combat commissions within 90 days to 120 days of not flying. It generally takes 60 days to 90 days to train the crews to mission-ready status.

Air Combat Command announced Tuesday that it would ground one-third of the active-duty fighters and bombers, including F-16 Falcons, the stealthy F-22 Raptors, and some of the bombers and airborne warning and control aircraft. Most of the impact would be in the United States, including fighter wings at air bases in Arizona, Florida, Idaho, North Carolina, South Carolina and Virginia, as well as bombers in South Dakota.

The squadrons not affected would include those that are deployed, preparing to deploy or are critical for the military’s nuclear capabilities.

The military services have been unveiling cuts in recent weeks in response to Congress’ move to cut funding by about $41 billion beginning March 1. Overall, the Pentagon faces $487 billion in cuts over the next decade, plus tens of billions of dollars more from the congressionally-ordered automatic cuts, which include the $41 billion for this current fiscal year that ends Sept. 31.